This invention relates to an automatic coupling mechanism and, more particularly, to an automatic coupling mechanism for coupling a propelling vehicle to a snow-plow and the like and for supporting the plow and for allowing free vertical movement of the plow with respect to the road surface as the plow is propelled by the vehicle along the road.
The prior art contains many structures for coupling a propelling vehicle to a snow-plow and for supporting such plow with respect to the road surface. However, such prior art structures are plagued by a number of disadvantages. One of the serious disadvantages of such prior art structures is that the structure which is used for supporting the plow must be attached to the main frame and, in addition, in some cases, the axle of the propelling vehicle. In addition, such prior art structures, although providing sufficient stability for supporting and carrying the plow, do not allow a free vertical movement of the plow with respect to the supporting structure in accordance with the undulations and unevenness of the road as the plow is propelled by the vehicle along the road. Often the plow is not rigidly and stably supported by the structure. Some prior art mechanisms provide the vertical movement of the plow by transverse or vertical motion of a pin located in a vertically elongated slot arrangement such as that shown in the Husting U.S. Pat. No. 2,710,464. In this particular prior art structure, the plow frame structure must be connected to the main structure or frame of the propelling vehicle, as well as coupled to the axle of the vehicle. In addition, great stress and wear occur to the structure where the pin rides in the elongated slot which allows for limited vertical movement of the plow with respect to the frame structure. Also the Husting structure requires that the plow support bars be rigidly welded between the frame structure and the plow or plow frame structure. Therefore, the only vertical motion allowed the plow is provided by the pin and slot arrangement which has a tendency to rapidly wear and deteriorate because of the heavy mass of the plow and plow frame support.
The advantages of the present invention are to provide the combination of a very stable and rigid support for the plow while at the same time allowing as free a floating motion as possible for the plow in a vertical direction with respect to the supporting structure as the vehicle propels the plow along the road. In addition, the present invention does not require that the supporting structure for the plow be in any way attached to the axle or other frame portion of the propelling vehicle. The coupling mechanism of the present invention allows a very rapid connection and disconnection of the plow to the propelling vehicle with a minimal effort on the part of the operator. And most importantly, the structure of the present invention allows the greatest possible floating action of the plow with respect to the undulations and unevenness of the road and free movement with respect to the support structure, while at the same time providing a very rigid and unyielding frame structure for supporting the weight of the plow. The coupling mechanism of the present invention provides the plow with a very free ability to rise and fall witha the surface of the road while simultaneously maintaining and controlling the orientation of the plow with respect to the supporting structure.